搜题请搜索小程序“爱下问搜题”
问题 计算题

一位同学欲配制6 mol/L的H2SO4溶液。他找来了三种不同浓度的硫酸：

①240 mL 1 mol/L的硫酸；

②150 mL 25%的硫酸（p=l. 18 g/mL）；

③足量的 18 mol/L的浓硫酸。

另外，他找来了三种规格的容量瓶：250 mL容量瓶；500 mL容量瓶；1000 mL容量瓶。这位同学希望将①②两种硫酸全部用完，不足部分再由③补充。请通过计算，帮助这位同学确定选用哪种规格的容量瓶，以及需要浓硫酸的体积是多少。

答案

用1000 mL容量瓶，需要295mL浓硫酸。

单项选择题

7月，南方某500头母猪群，卫生状况较差，近一周内不同胎次母猪在妊娠后期发生流产，产死胎，木乃伊胎和弱仔。公猪体温高达41至42℃，随后出现一侧或两侧睾丸肿大，嗜睡等症状，剖检流产胎儿见大脑和小脑发育不全，液化性坏死。

该病常用的免疫学诊断方法是（）

A、中和实验

B、血凝与血凝抑制试验

C、Ascoli反应

D、变态反应

E、试管凝集试验
查看答案
单项选择题

She’s cute, no question. Symmetrical features, flawless skin, looks to be 22 years old—entering any meat-market bar, a woman lucky enough to have this face would turn enough heads to stir a breeze. But when Victor Johnston points and clicks, the face on his computer screen changes into a state of superheated, crystallized beauty. "You can see it. It’s just so extraordinary," says Johnston, a professor of biopsychology at New Mexico State University who sounds a little in love with his creation.
The transformation from pretty woman to knee-weakening babe is all the more amazing because the changes wrought by Johnston’s software are, objectively speaking, quite subtle. He created the original face by digitally averaging 16 randomly selected female Caucasian faces. The changing program then exaggerated the ways in which female faces differ from male faces, creating, in humanbeauty-science field, a "hyper-female". The eyes grew a bit larger, the nose narrowed slightly and the lips plumped. These are shifts of just a few millimeters, but experiments in this country and Scotland are suggesting that both males and females find "feminized" versions of averaged faces more beautiful.
Johnston hatched this little movie as part of his ongoing study into why human beings find some people attractive and others homely. He may not have any rock-solid answers yet, but he is far from alone in attempting to apply scientific inquiry to so ambiguous a subject. Around the world, researchers are marching into territory formerly staked out by poets and painters to uncover the underpinnings of human attractiveness.
The research results so far are surprising—and humbling. Numerous studies indicate that human beauty may not be simply in the eye of the beholder or an arbitrary cultural artifact. It may be ancient and universal, wrought through ages of evolution that rewarded reproductive winners and killed off losers. If beauty is not truth, it may be health and fertility: Halle Berry’s flawless skin may fascinate moviegoers because, at some deep level, it persuades us that she is parasite-free.
Human attractiveness research is a relatively young and certainly contentious field—the allure of hyper-females, for example, is still hotly debated—but those on its front lines agree on one point: We won’t conquer "looks-ism" until we understand its source. As psychologist Nancy Etcoff puts it: "The idea that beauty is unimportant or a cultural construct is the real beauty myth. We have to understand beauty, or we will always be enslaved by it. \

The word "exaggerated" underlined in Paragraph 2 is closest in meaning to ______.

A．overstate

B．magnify

C．overdraw

D．aggrandize
查看答案